What happens to the force between two charges if the magnitude of both charges is doubled and the distance between them is cut in half?

Cathy is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25 meters high, without pedaling. cathy and her bicycle have a mass of 75 kg. assuming her bicycle is 100% efficient, what would her speed have to be?

What is the relationship between the direction of motion of the balloon and the wind currents

Matter that emits no light at any wavelength is called